The current Foreign Office travel advice for Jordan warns against travel close to the Syrian border, for obvious reasons. Travel to other areas of Jordan is fine. You should familiarise yourself with the information they provide about safety etc. although most of it is common sense.
It also says that over sixty thousand British nationals visited Jordan in 2015, so it is not such a rare occurrence that they would scrutinise someone just for having been there.
As a UK citizen, you may not even need to interact with immigration officials at all. If you have an e-passport and are travelling to an airport/terminal that has them you can use the e-passport gates, and avoid human interaction pretty much entirely.